1. Field of the Invention
The present invention relates generally to a speaker structure, which has a greatly minified volume and is manufactured at lower cost.
2. Description of the Related Art
In recent years, along with the miniaturization of various digital electronic products and video/audio products such as audiphones and earphones, the speakers installed on these products have been more and more required to be thinned, miniaturized and lightweight. Also, the dynamic range of the output signal of these products is enlarged so that the speakers are required to have higher output volume.
The speaker is a kind of converter for converting electrical energy into sonic energy through physical effect. According to different physical effects of conversion between electrical energy and sonic energy, the speakers can be classified into many types such as electromagnetic speakers, piezoelectric speakers, capacitive speakers or electrical speakers. In these speakers, the electrical speaker has a relatively simple structure and good performance so that the electrical speaker is popularly used as a mainstream of the currently developed and produced speakers.
According to the different effects of the respective parts of the speaker, the basic structure of the speaker can be classified into three parts of vibration system, magnetic circuit system and auxiliary system. Please refer to FIG. 1, which is a sectional view of a conventional speaker structure 1. The conventional speaker structure 1 includes a magnetic circuit system composed of a basin support 10, an upper board (washer) 11, a lower board (T-iron) 12 and a magnet 13. The speaker structure 1 further has a vibration membrane 14. In addition, a transitional dangling edge 15 is connected between the vibration membrane 14 and the basin support 10 for achieving better smoothness of the vibration system of the speaker. The dangling edge 15 is generally integrated with the vibration membrane 14. The speaker structure 1 further has a damper 16 mainly for supporting and locating the vibration system of the speaker 1. In addition, the speaker structure 1 includes a voice coil 17 as a drive source of the vibration system of the speaker 1. The voice coil 17 is generally composed of a voice coil collar and windings.
The working principle of the speaker is that the current intensity and the direction of the force applied to the voice coil are changed so that the voice coil is back and forth vibrated in the magnetic gap. The period or frequency of the vibration is equal to the period or frequency of the input current. The amplitude of the vibration is in direct proportion to the instantaneous intensity of the acting current. The woofer vibration membrane and the tweeter vibration membrane are fixed on the voice coil so that the voice coil can drive the woofer vibration membrane and the tweeter vibration membrane to up and down vibrate and radiate sonic wave. Accordingly, the electrical energy is converted into sonic energy.
However, under the affection of the conventional speaker structure, there must be a certain buffering distance between the voice coil and the magnet. Also, there must be a certain buffering distance between the vibration membrane and the damper and there must be a certain buffering distance between the dangling edge and the basin support. Therefore, the total thickness of the speaker is considerably large. As a result, the conventional speaker can be hardly thinned. Due to the limitation of the thickness, the conventional speaker can be hardly applied to the current thin electronic products.
Furthermore, the conventional speaker is composed of numerous components and is manufactured by a complicated process. Therefore, it is quite time-consuming to produce the conventional speaker and the manufacturing cost of the conventional speaker is quite high.
According to the above, the conventional speaker structure has the following shortcomings:    1. The volume and thickness of the conventional speaker are considerably large so that the conventional speaker cannot be applied to the current thin electronic products.    2. The manufacturing cost of the conventional speaker is quite high and the working time of the conventional speaker is relatively long.